Brain MRS glutamine as a biomarker to guide therapy of hyperammonemic coma.

Abstract

Acute idiopathic hyperammonemia in an adult patient is a life-threatening condition often resulting in a rapid progression to irreversible cerebral edema and death. While ammonia-scavenging therapies lower blood ammonia levels, in comparison, clearance of waste nitrogen from the brain may be delayed. Therefore, we used magnetic resonance spectroscopy (MRS) to monitor cerebral glutamine levels, the major reservoir of ammonia, in a gastric bypass patient with hyperammonemic coma undergoing therapy with N-carbamoyl glutamate and the ammonia-scavenging agents, sodium phenylacetate and sodium benzoate. Improvement in mental status mirrored brain glutamine levels, as coma persisted for 48h after plasma ammonia normalized. We hypothesize that the slower clearance for brain glutamine levels accounts for the delay in improvement following initiation of treatment in cases of chronic hyperammonemia. We propose MRS to monitor brain glutamine as a noninvasive approach to be utilized for diagnostic and therapeutic monitoring purposes in adult patients presenting with idiopathic hyperammonemia.

• Authors: Anne H O'Donnell-Luria, Alexander P Lin, Sai K Merugumala, Frances Rohr, Susan E Waisbren, Rebecca Lynch, Vatche Tchekmedyian, Aaron D Goldberg, Andrew Bellinger, J Ricardo McFaline-Figueroa, Tracey Simon, Esteban F Gershanik, Bruce D Levy, David E Cohen, Martin A Samuels, Gerard T Berry, Natasha Y Frank
• Journal: Molecular genetics and metabolism (Mol Genet Metab) Vol. 121 Issue 1 Pg. 9-15 (05 2017) ISSN: 1096-7206 [Electronic] United States
• PMID: 28408159 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical References

• Glutamates
• Phenylacetates
• Glutamine
• N-carbamylglutamate
• phenylacetic acid
• Sodium Benzoate

Topics

• Brain (diagnostic imaging, metabolism)
• Coma (drug therapy, etiology)
• Female
• Gastric Bypass (adverse effects)
• Glutamates (therapeutic use)
• Glutamine (metabolism)
• Humans
• Hyperammonemia (complications, diagnostic imaging, drug therapy, metabolism)
• Magnetic Resonance Spectroscopy (methods)
• Middle Aged
• Phenylacetates (therapeutic use)
• Sodium Benzoate (therapeutic use)
• Treatment Outcome